A heat exchanger of the automotive type in which spaced parallel coolant tubes extend between a pair of header tanks for conveying the coolant through the tubes from one tank to the other and with the space between adjacent tubes being spanned by serpentine fins is a common construction used not only in automotive equipment but in other types of heat exchangers.
The difficulty in assembling such a exchanger is that serpentine fins which are normally made of very thin metal such as aluminum are so flexible that they are hard to handle in making the heat exchanger. By the method of this invention each flexible serpentine fin is first assembled in a rigid unit by attaching the heat conducting members to the opposite crests of the fin so that the assembly of the fin and rigid members is inflexible and can easily be inserted into the space between adjacent tubes and attached in heat conducting relationship to the tubes.
In the completed heat exchanger these rigid members that are attached to the crests of the serpentine fin are also formed of heat conducting material such as metal of the order of aluminum, steel and the like so that these members themselves contribute to the heat exchange efficiency of the heat exchanger.